In ISE design tools 11.4.1 and later, when using the SPI-3 Link Layer v6.1 or v7.1 Core targeting a Virtex-6 device, an error similar to the following might occur in MAP:
"ERROR:PhysDesignRules:1997 - The computed value for the VCO operating frequency of MMCM_ADV instance rfmmcm is calculated to be 415.999983 MHz. This falls below the operating range of the MMCM VCO frequency for this device of 600.000000 - 1200.000000 MHz. Please adjust either the input frequency CLKINx_PERIOD, multiplication factor CLKFBOUT_MULT_F or the division factor DIVCLK_DIVIDE, in order to achieve a VCO frequency within the rated operating range for this device.
ERROR:PhysDesignRules:2063 - A CLKFBOUT_MULT_F setting of 4.0 for MMCM_ADV (block rfmmcm) cannot be supported at this time.
ERROR:PhysDesignRules:1997 - The computed value for the VCO operating frequency of MMCM_ADV instance tfmmcm is calculated to be 415.999983 MHz. This falls below the operating range of the MMCM VCO frequency for this device of 600.000000 - 1200.000000 MHz. Please adjust either the input frequency CLKINx_PERIOD, multiplication factor CLKFBOUT_MULT_F or the division factor DIVCLK_DIVIDE, in order to achieve a VCO frequency within the rated operating range for this device.
ERROR:PhysDesignRules:2063 - A CLKFBOUT_MULT_F setting of 4.0 for MMCM_ADV (block tfmmcm) can not be supported at this time.
ERROR:Pack:1642 - Errors in physical DRC."